Head-mounted display device and method of changing light transmittance of the same

ABSTRACT

A method of changing a light transmittance of a head-mounted display device including a display and an optical lens and a head-mounted display device. The method includes obtaining, by a sensor, a first illuminance around the head-mounted display device; determining a first light transmittance based on the first illuminance and a type of a content to display on the display; changing, by a processor, a light transmittance of the optical lens to the first light transmittance; and wherein when the first illuminance is greater than a second illuminance, the first light transmittance corresponding to the first illuminance is less than a second light transmittance corresponding to the second illuminance.

PRIORITY

This continuation application application claims priority under 35U.S.C. § 120 to a U.S. patent application filed on Nov. 11, 2014 in theUnited States Patent and Trademark Office and assigned Ser. No.14/538,456, which claims priority under 35 U.S.C. § 119(a) to a KoreanPatent Application filed on Nov. 18, 2013 in the Korean IntellectualProperty Office and assigned Serial No. 10-2013-0140188, the entirecontents of each of which are incorporated herein by reference.

BACKGROUND 1. Field of the Invention

The present invention relates generally to a head-mounted display deviceand a method of changing a light transmittance of the head-mounteddisplay device, and more particularly, to a head-mounted display devicethat changes a light transmittance light of a transmission unit using alight transmittance determined to correspond to an illuminance and anapplication, and a method of changing the light transmittance of thehead-mounted display device.

2. Description of the Related Art

Recently, various services and functions provided by portable deviceshave been gradually expanded. In addition, various applications capableof being executed in portable devices have also been developed.

In order to enhance the utility of such portable devices and satisfyusers' various desires, various portable devices, such as wrist-mountedportable devices and head-mounted portable devices, have been developed.

Light incident on a head-mounted portable device is not 100% transmittedand, thus, may look darker than the light actually is. In addition, whenthe intensity of incident light is strong, the head-mounted portabledevice may consume more battery power and may generate heat in order todisplay a text, an image or a video displayed on a display unit morebrightly to correspond to the incident light.

SUMMARY

The present invention has been made to address the above-mentionedproblems and disadvantages, and to provide at least the advantagesdescribed below. Accordingly, an aspect of the present invention, thereis provided a method of changing a light transmittance of a head-mounteddisplay device and the head-mounted display device to provide the userwith improved visibility of a content displayed.

In accordance with an aspect of the present invention, there is provideda method of changing a light transmittance of a head-mounted displaydevice including a display and an optical lens and a head-mounteddisplay device. The method includes obtaining, by a sensor, a firstilluminance around the head-mounted display device; determining a firstlight transmittance based on the first illuminance and a type of acontent to display on the display; changing, by a processor, a lighttransmittance of the optical lens to the first light transmittance; andwherein when the first illuminance is greater than a second illuminance,the first light transmittance corresponding to the first illuminance isless than a second light transmittance corresponding to the secondilluminance.

In accordance with another aspect of the present invention, there isprovided a head-mounted display device. The head-mounted display deviceincludes a sensor; a display; a light transmission unit configured toadjust a light transmittance of an optical lens included in thehead-mounted display device; and a controller configured to obtain,using the sensor, a first illuminance around the head-mounted displaydevice, determine a first transmittance based on the first illuminanceand a type of the content to display on the display, and change thelight transmittance of the optical lens to the first lighttransmittance, wherein when the first illuminance is greater than asecond illuminance, the first light transmittance corresponding to thefirst illuminance is less than a second light transmittancecorresponding to the second illuminance.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the presentinvention will be more apparent from the following detailed description,taken in conjunction with the accompanying drawings, in which:

FIG. 1A is a perspective view illustrating a head-mounted display deviceaccording to an embodiment of the present invention;

FIG. 1B is an exploded view of a light transmission unit of ahead-mounted display device according to an embodiment of the presentinvention;

FIG. 2 is a schematic block diagram illustrating a head-mounted displaydevice according to an embodiment of the present invention;

FIG. 3 is a flowchart illustrating a method of changing a lighttransmittance of a head-mounted display device according to anembodiment of the present invention;

FIGS. 4A to 4E are illustrations of a method of changing a lighttransmittance of a head-mounted display device according to anembodiment of the present invention;

FIGS. 5A and 5B are illustrations of a method of changing a lighttransmittance of a head-mounted display device according to anembodiment of the present invention;

FIGS. 6A and 6B are illustrations of a method of changing a lighttransmittance of a head-mounted display device according to anembodiment of the present invention;

FIGS. 7A and 7B are illustrations of a method of changing a lighttransmittance of a head-mounted display device according to anembodiment of the present invention; and

FIGS. 8A and 8B are illustrations of a method of changing a lighttransmittance of a head-mounted display device, according to anembodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

Hereinafter, embodiments of the present invention are described indetail with reference to the accompanying drawings. Further, the methodsof manufacturing and using the present invention are described in detailwith reference to the accompanying drawings. The same reference numeralsor the signs represented in each of the drawings indicate the elementsor the components that perform substantially the same functions.

Although terms including an ordinal number such as first, second, etc.may be used for describing various elements, the structural elements arenot restricted by the terms. The terms are only used to distinguish oneelement from another element. For example, without departing from thescope of the present invention, a first structural element may bereferred to as a second structural element. Similarly, the secondstructural element may also be referred to as the first structuralelement. As used herein, the term “and/or” includes any and allcombinations of one or more associated items.

In the present invention, the terms are used to describe an embodiment,and are not intended to limit and/or restrict the present invention. Asused herein, the singular forms are intended to include the plural formsas well, unless the context clearly indicates otherwise. In the presentinvention, the terms such as “include” and/or “have” may be construed todenote a certain characteristic, number, step, operation, constituentelement, component or a combination thereof, but may not be construed toexclude the existence of or a possibility of addition of one or moreother characteristics, numbers, steps, operations, constituent elements,components or combinations thereof. The same reference numeralsrepresented in each of the drawings indicate the elements that performsubstantially the same functions.

FIG. 1A is a perspective view illustrating a head-mounted display deviceaccording to an embodiment of the present invention.

Referring to FIG. 1A, a head-mounted display device 100 refers to adisplay device which is wearable on a user's head. A see-through displayunit is positioned in a region adjacent to the user's head (e.g., eyes),and a speaker (not illustrated) is positioned in a region adjacent tothe user's ears so that visual information and auditory information canbe provided to the user. The head-mounted display device 100 includes aneyeglass type display device or a helmet type display device.

The head-mounted display device 100 includes a monocular-type displaydevice having a single display unit 190 that displays contents or abinocular-type display device having a plurality of display units 190and 190 a that may display a three-dimensional image. The binocular-typedisplay device may selectively operate one of the plurality of displayunits 190 and 190 a.

The head-mounted display device 100 includes a first optical lens 10, afirst housing 20 that accommodates a part of the first optical lens 10,a second housing 30 that includes a battery, a first housing connectionportion 25 that connects the first housing 20 and the second housing 30.In addition, the head-mounted display device 100 includes a secondoptical lens 10 a, a third housing 20 a that accommodates a part of thesecond optical lens 10 a, a fourth housing 30 a that includes a battery,and a second housing connection portion 25 a that connects the thirdhousing 20 a and the fourth housing 30 a. The battery may be positionedin the first housing 20, the second housing 30, the third housing 20 a,or the fourth housing 30 a.

The head-mounted display device 100 is mounted on the user's head by theelastically flexible first housing connection portion 25 and the secondhousing connection portion 25 a.

The head-mounted display device 100 includes a bridge 21 that connectsthe first housing 20 and the third housing 20 a.

The head-mounted display device 100 includes a light transmission unit195 (see FIG. 1B) if a single display unit 190 is included, or aplurality of light transmission units 195 if a plurality of displayunits 190 and 190 a are included. The light transmission unit 195 iscoupled to the rear surface of the second optical lens 10 a using anoptically clear adhesive. The light transmission unit 195 may be coupledto the rear surface of the first optical lens 10 using an opticallyclear adhesive. In addition, the light transmission unit 195 is coupledto the front surface of the first optical lens 10 and the second opticallens 10 a, respectively, using an optically clear adhesive.

The display unit 190 or 190 a is positioned at a distance (e.g., notmore than 5 cm) from at least one of the front surface of the firstoptical lens 10 or the second optical lens 10 a, respectively, orpositioned at a distance (e.g. not more than 5 cm) from the rear surfaceof the first optical lens 10 or the second optical lens 10 a,respectively. A person having an ordinary skill in the art may easilyunderstand that the spacing between the display units 190 or 190 a andthe first optical lens 10 or the second optical lens 10 a, respectively,may be changed to correspond to a performance or a structure of thehead-mounted display device 100.

The head-mounted display device 100 includes a camera unit 150 (see FIG.2, where the camera unit 150 may include a first camera 151, a secondcamera 152, and a third camera not shown) and a sensor unit 170 (seeFIG. 2, where the sensor unit includes a plurality of sensors). Thecamera unit 150 is positioned in at least one of the first housing 20and the third housing 20 a. For example, the camera unit 150 may bepositioned in one of the first housing 20 and the third housing 20 a orthe first camera 151 of the camera unit 150 may be positioned in thefirst housing 20 and the second camera 152 of the camera unit 150 may bepositioned in the third housing 20 a. Further, the third camera of thecamera unit 150 may be positioned in the bridge 21.

The sensor unit 170 is positioned in at least one of the first housing20 and the third housing 20 a. For example, the sensor unit 170 may bepositioned in one of the first housing 20 and the third housing 20 a orthe sensors of the sensor unit may be positioned in each of the firsthousing 20 and the third housing 20 a. Further, a sensor of the sensorunit 170 may be positioned in the bridge 21.

The first housing 20 of the head-mounted display device 100 includes atleast one of a button 161 (see FIG. 2), a microphone 162 (see FIG. 2), aspeaker 163 (see FIG. 2), a connector 164, and a touch pad 165 (see FIG.2). The term “housing” in the present invention includes the firsthousing 20, the second housing 30, the third housing 20 a, or the fourthhousing 30 a.

It may be easily understood by a person ordinarily skilled in the artthat the positions of the constituent elements of the head-mounteddisplay device 100 illustrated in FIG. 1A may be changed to correspondto the performance or structure of the head-mounted display device 100.

FIG. 1B is a perspective view of a light transmission unit 195 of thehead-mounted display device 100 according to an embodiment of thepresent invention.

Referring to FIG. 1B, a light transmission unit 195 is coupled to therear surface of the second optical lens 10 a. Alternatively, a lighttransmission unit 195 may be coupled to the front surface of the secondoptical lens 10 a.

The light transmission unit 195 includes a first indium tin oxide layer195 a, an electrochromic layer 195 b, an electrolyte layer 195 c, asecond indium tin oxide layer 195 d, and electrodes 195 e. Hereinafter,each indium tin oxide layer will be referred to as an Indium Tin Oxide(ITO) layer. The term, “ITO layer” may include an ITO film or an ITOglass. In addition, an ITO layer may be implemented using a silver nanowire, a copper mesh, a silver mesh, a silver salt, or silvernanoparticles which may replace the ITO.

The light transmission unit 195 includes a first ITO layer 195 a, anelectrochromic layer 195 b positioned on the ITO layer 195 a and havinga light transmittance which is changed to correspond to a supplyvoltage, an electrolyte layer 195 c positioned on the electrochromiclayer 195 b, a second ITO layer 195 d positioned on the electrolytelayer 195 c, and electrodes 195 e which are connected with the first ITOlayer 195 a and the second ITO layer 195 d, respectively, and receivesan input of the supply voltage.

Each of the electrodes 195 e is implemented as a transparent electrode.It may be easily understood by a person ordinarily skilled in the artthat the position of each electrode 195 e (e.g., a right upper end ofthe first ITO layer 195 a or a left upper end of the second ITO layer195 d) may be changed to correspond to the performance or structure ofthe head-mounted display device 100.

FIG. 2 is a schematic block diagram illustrating a head-mounted displaydevice 100 according to an embodiment of the present invention.

Referring to FIG. 2, a head-mounted display device 100 is connected withan external device (not illustrated) wiredly or wirelessly using amobile communication unit 120, a sub-communication unit 130, and aconnector 164. The external device may include a portable phone (notillustrated) which includes a screen having an area wider than that ofeach of the plurality of display units 190 or 190 a, a smart phone (notillustrated), a tablet Personal Computer (PC) (not illustrated), aMotion Picture Experts Group Audio Layer 3 (MP3) player, a video imageplayer, a 3 Dimensional Television (3D-TV), a smart TV, an LightEmitting Diode (LED) TV, an Liquid Crystal Display (LCD) TV, or a server(not illustrated). In addition, the external device may include anotherhead-mounted display device (not illustrated).

The head-mounted display device 100 includes a device capable oftransmitting/receiving data (e.g., an image, a text, a voice, or avideo) with another connectable external device using a user input (or auser interaction, for example, a voice, a motion, a touch or a touchgesture) which is input via a head-mounted display device 100.

The head-mounted display device 100 includes a display unit 190 and alight transmission unit 195. The head-mounted display device 100includes a control unit 110, a mobile communication unit 120, asub-communication unit 130, a multimedia unit 140, a camera unit 150, aGlobal Positioning System (GPS) unit 155, an input/output unit 160, asensor unit 170, a storage unit 175, and a power supply unit 180.

The sub-communication unit 130 includes at least one of a wireless LocalArea Network (LAN) unit 131 and a short-range communication unit 132,and the multimedia unit 140 includes at least one of an audioreproducing unit 141 and a video reproducing unit 142. The camera unit150 includes at least one of a first camera 151 and a second camera 152,the input/output unit 160 includes at least one of a button 161, amicrophone 162, a speaker 163, a connector 164, and a touch pad 165. Thesensor unit 170 includes an illuminance sensor 171, a proximity sensor172, and a gyro sensor 173.

The control unit 110 includes a processor 111, a Read-Only Memory (ROM)112 in which a control program for controlling the head-mounted displaydevice 100 is stored, and an Random Access Memory (RAM) 113 which may beused as a region to store a signal or data input received by thehead-mounted display device 100 or a storage region for various tasksperformed by the head-mounted display device 100.

The control unit 110 controls overall action of the head-mounted displaydevice 100 and signal flow between the elements 120 to 195 of thehead-mounted display device 100, and processing data. The control unit110 controls a power supply, from the power supply unit 180, to theelements 120 to 195. In addition, when a user input or a set conditionthat is stored is satisfied, the control unit 110 executes an OperatingSystem (OS) and various applications stored in the storage unit 175.

The processor 111 includes a Graphics Processing Unit (GPU) (notillustrated) for graphic processing. The processor 111 may beimplemented as a core (not illustrated) and the GPU (not illustrated)may be implemented as a System on Chip (SoC). The processor 111 mayinclude a single core, dual cores, triple cores, quad cores, and coresof multiples thereof. In addition, the processor 111, the ROM 112, andthe RAM 113 are interconnected via an internal bus.

The control unit 110 controls the mobile communication unit 120, thesub-communication unit 130, the multimedia unit 140, the camera unit150, the GPS unit 155, the input/output unit 160, the sensor unit 170,the storage unit 175, the power supply unit 180, the display unit 190,and the light transmission unit 195.

In the present invention, the term “control unit” includes the processor111, the ROM 112, and the RAM 113.

The control unit 110 of an embodiment of the present invention detectsan illuminance to determine an application to be displayed on thedisplay unit 190 of the head-mounted display device 100, to determine alight transmittance corresponding with the illuminance and theapplication, and to change the light transmittance of the lighttransmission unit 195 of the head-mounted display device 100 to thedetermined light transmittance.

The control unit 110 determines a supply voltage corresponding to thedetermined light transmittance, and supplies the determined supplyvoltage to the light transmission unit 195.

The control unit 110 uses at least one of the illuminance detected viathe sensor unit 170 and an illuminance received externally as theilluminance.

The control unit 110 determines an application using at least one ofinformation of the application and contents executed by the application.

The control unit 110 uses at least one of a program manager that managesa life cycle of an application executed in the head-mounted displaydevice 100 and an application specification file in which theapplication information is described in determining the application.

The control unit 110 determines an application using an activity manageror a package manager as the program manager.

The control unit 110 causes the determined light transmittance to bechanged by a user input.

The control unit 110 causes the visibility of the contents displayed onthe display unit 190 to be changed by the light transmittance of thelight transmission unit 195.

The control unit 110 causes the determined light transmittance to bechanged in a range from 5% to 95%.

The control unit 110 provides at least one of a visual feedback and anauditory feedback in response to a change of the light transmittance.

The control unit 110 detects the illuminance to determine the contentsto be displayed on the display unit 190 of the head-mounted displaydevice 100, and to change the light transmittance of the lighttransmission unit 195 of the head-mounted display device 100 accordingto the light transmittance determined according to the illuminance andthe contents.

The control unit 110 determines an application to be displayed on thedisplay unit 190 of the head-mounted display device 100, and changes thelight transmittance of the light transmission unit 195 of thehead-mounted display device 100 according to the determined lighttransmittance to correspond to the application.

The mobile communication unit 120 is connected with an external devicewiredly or wirelessly using one or more antennas according to thecontrol unit 110. The mobile communication unit 120 transmits/receiveswireless signals for voice communication, video communication, ShortMessage Service (SMS), Multimedia Message Service (MMS), or datacommunication with a portable phone having a phone number connectablewith the head-mounted display device 100, a smart phone (notillustrated), a tablet PC or another head-mounted display device (notillustrated).

The sub-communication unit 130 includes at least one of the wireless LANunit 131, and the short-range communication unit 132. For example, thesub-communication unit 130 may include only one of the wireless LAN unit131 and the short-range communication unit 132 or both the wireless LANunit 131 and the short-range communication unit 132.

The wireless LAN unit 131 may be wirelessly connected to an Access Point(AP) in a place where the AP (not illustrated) is installed according tothe control unit 110. The wireless LAN unit 131 supports the WirelessLAN Standards (IEEE802.11x) of the Institute of Electrical andElectronics Engineers (IEEE).

The short-range communication unit 132 provides short-rangecommunication between the head-mounted display device 100 and anexternal device wirelessly without the AP according to the control unit110. The short-range communication unit 132 may include, for example,Bluetooth, Bluetooth Low Energy, Infra-red Data Association (IrDA),Wireless Fidelity (Wi-Fi), Ultra Wideband (UWB), and Near FieldCommunication (NFC).

The head-mounted display device 100 includes, depending on itsperformance, at least one of the mobile communication unit 120, thewireless LAN unit 131, and the short-range communication unit 132. Forexample, depending on performance, the head-mounted display device 100includes one of the mobile communication unit 120, the wireless LAN unit131, short-range communication unit 132, and a combination of the mobilecommunication unit 120, the wireless LAN unit 131, and the short-rangecommunication unit 132.

In the present invention, the term “communication unit” includes themobile communication unit 120 and the sub-communication unit 130.

The mobile communication unit 120 of an embodiment of the presentinvention connects the head-mounted display device 100 and an externaldevice according to the control unit 110. The mobile communication unit120 transmits data or contents to an external device according to thecontrol unit 110. In addition, the mobile communication unit 120transmits/receives data to/from an external device according to thecontrol unit 110. In addition, the mobile communication unit 120receives an illumination reception from an external device according tothe control unit 110.

The multimedia unit 140 includes the audio reproducing unit 141 or thevideo reproducing unit 142.

The audio reproducing unit 141 reproduces an audio source previouslystored in the storage unit 175 of the head-mounted display device 100 orreceived from an external source (for example, an audio file, of whichthe file extension is mp3, Windows Media Audio (wma), Operation GoodGuys (ogg), or Waveform Audio File (way)) using an audiocompression/decompression (codec) unit according to the control unit110.

The audio reproducing unit 141, according to an embodiment of thepresent invention, reproduces an auditory feedback corresponding to achange of the light transmittance of the light transmission unit 195(e.g., output of the audio source stored in the storage unit 175) usingthe audio codec unit according to the control unit 110.

The video reproducing unit 142 reproduces a digital video sourcepreviously stored in the storage unit 175 of the head-mounted displaydevice 100 or received from an external source (for example, a file, ofwhich the file extension is Moving Picture Expert Group (mpeg or mpg),MPEG Audio Layer 4 (mp4), Audio Video Interleave (avi), Quick Time Movie(mov), Small Web Format (swf), Macromedia Flash (fla), or Matroska VideoFormat (mkv)) using a video codec unit according to the control unit110. Almost all of the reproducing applications, which are capable ofbeing executed in the head-mounted display device 100, reproduce anaudio source or video file using the audio codec unit or the video codecunit. In addition, almost all of the reproducing applications, which arecapable of being executed in the head-mounted display device 100,reproduce an audio source or still image file.

The video reproducing unit 142, according to an embodiment of thepresent invention, reproduces a visual feedback corresponding to achange of the light transmittance of the light transmission unit 195(for example, output of a video source stored in the storage unit 175)using the video codec unit according to the control unit 110.

It may be easily understood by a person ordinarily skilled in the artthat various types of video and audio codec units are manufactured andsold.

The audio reproducing unit 141 or the video reproducing unit 142 of themultimedia unit 140 may be included in the control unit 110. The term“video codec unit” in an embodiment of the present invention may includeone or more video codec units. In addition, the term “audio codec unit”in an embodiment of the present invention includes one or more audiocodec units.

The camera unit 150 photographs a still image or a moving image in auser's line of sight according to the control unit 110. The camera unit150 may be positioned in at least one of the bridge 21, the firsthousing 20, and the third housing 20 a. For example, the camera unit 150may be positioned in one of the bridge 21, the first housing 20, and thethird housing 20 a; or the camera unit 150 may be positioned in two ormore of the bridge 21, the first housing 20, and the third housing 20 a.When including one camera, the head-mounted display device 100 includesthe first camera 151. When including two or more cameras, thehead-mounted display device 100 includes the first camera 151 and thesecond camera 152.

The head-mounted display device 100 may include a third camera (notillustrated) which may be positioned in one of the second housing 30 andthe fourth housing 30 a of the head-mounted display device 100 and iscapable of photographing a still image or a moving image behind theuser. In addition, the first camera 151 or the second camera 152 mayinclude an auxiliary light source that provides an amount of lightrequired for photographing (for example, a flash 153).

When the first camera 151 and the second camera 152 are positionedadjacent to each other (for example, the distance between the firstcamera 151 and the second camera 152 is larger than 2 cm and smallerthan 8 cm), the first camera 151 and the second camera 152 mayphotograph a three-dimensional still image or a three-dimensional movingimage according to the control unit 110. In addition, one of the firstcamera 151 and the second camera 152 may take a photograph includingwide angle photography, telephotography, and close-up photography usinga separate adaptor (not illustrated).

The camera unit 150, according to an embodiment of the presentinvention, may photograph a still image or a moving image around thehead-mounted display device 100 and transmit the still image or themoving image to the control unit 110. The control unit 110 transmits thereceived still image or moving image to an external device using themobile communication unit 120. In addition, the control unit 110calculates the illumination around the head-mounted display device 100using the photographed still image or moving image.

The GPS unit 155 periodically receives information (for example, correctposition information or time information from a GPS satellite from whichthe head-mounted display device 100 is capable of receiving a signal)from a plurality of GPS satellites orbiting the earth. The head-mounteddisplay device 100 determines the present position, moving speed, ortime of the head-mounted display device 100 using the informationreceived from the plurality of GPS satellites.

The input/output unit 160 includes one or more buttons 161, one or moremicrophones 162, one or more speakers 163, one or more connectors 164,or one or more touch pads 165.

Referring to FIGS. 1 and 2, the button 161 includes a power/lock buttonpositioned on the first housing 20. The button 161 may include a homebutton on the first housing 20. In addition, the button 161 may beimplemented not only as a physical button but also as a touch button onthe housings of the head-mounted display device 100.

The microphone 162 receives a voice or a sound external to thehead-mounted display device 100 and generates an electrical signalaccording to the control unit 110. The electrical signal generated bythe microphone 162 is converted in the audio codec unit and stored inthe storage unit 175 or output via the speaker 163. One or moremicrophones 162 may be positioned in the first housing 20 and the thirdhousing 20 a of the head-mounted display device 100. In addition, one ormore microphones 162 may be positioned in the second housing 30 and thefourth housing 30 a of the head-mounted display device 100.

The speaker 163 outputs sounds corresponding to various contents of themobile communication unit 120, the sub-communication unit 130, themultimedia unit 140, the camera unit 150, or an application (forexample, a wireless signal, a broadcast signal, an audio source, a videofile, or a photograph) externally from the head-mounted display device100, using the audio codec unit, according to the control unit 110. Thespeaker 163 outputs a sound corresponding to a function performed by thehead-mounted display device 100 (for example, a touch operation soundcorresponding to inputting a phone number, or taking a photograph).

At least one speaker 163 may be positioned in the housing of thehead-mounted display device 100. Referring to FIGS. 1 and 2, the speaker163 may be positioned in a region of the housing of the head-mounteddisplay device 100 (for example, a region adjacent to a user's earcapable of receiving an output sound). In addition, the speaker 163 ofthe head-mounted display device 100 may include an air conductionspeaker or a bone conduction speaker.

The speaker 163, according to an embodiment of the present invention,outputs an auditory feedback corresponding to a change of the lighttransmittance of the light transmission unit 195 according to thecontrol unit 110.

The connector 164 connects the head-mounted display device 100 to anexternal device or a power source. The head-mounted display device 100transmits data stored in the storage unit 175 to an external device orreceives data from the external device via a wired cable connected tothe connector 164 according to the control unit 110. The head-mounteddisplay device 100 receives power from a power source connected to theconnector 164 via the wired cable, or a charge for a battery.

The touch pad 165 receives a user input (for example, a touch or a touchand drag) to control the head-mounted display device 100. The touch pad165 is planar (for example, a polygonal shape, a circular shape, an ovalshape, or a rounded-rectangular shape) and incorporates a sensor. Thetouch pad 165 is positioned on a side surface of a housing of thehead-mounted display device 100.

The user input of the touch pad 165 is not limited to contact by theuser's body or a touchable input unit (for example, a stylus pen) butincludes non-contact (for example, hovering in which a detectablespacing between the touch pad 165 and the user's body or between thetouch pad 165 and an input unit is 20 mm or less). It may be easilyunderstood by a person ordinarily skilled in the art that the detectablenon-contact spacing in the touch pad 165 may be changed depending on theperformance or structure of the head-mounted display device 100.

The head-mounted display device 100 may include one of a trackball and apointing stick which is compatible with the touch pad 165.

The sensor unit 170 includes at least one sensor which detects acondition of the head-mounted display device 100 or a peripheralcondition. For example, the sensor unit 170 is positioned on the frontsurface or a side surface of a housing of the head-mounted displaydevice 100. The sensor unit 170 may include an illuminance sensor 171which detects an amount of light around the head-mounted display device100, a proximity sensor 172 which detects proximity of any other objectin relation to the head-mounted display device 100, a gyro sensor 173which detects a slope of the head-mounted display device 100 usingrotational inertia of the head-mounted display device 100, anacceleration sensor which detects a moving condition of three axes (forexample, x-axis, y-axis, and z-axis) applied to the head-mounted displaydevice 100, a gravity sensor which detects an acting direction ofgravity, or an altimeter which detects an altitude by measuring anatmospheric pressure.

The illuminance sensor 171, according to an embodiment of the presentinvention, detects an illuminance around the head-mounted display device100. The illuminance sensor 171 transmits an illuminance signalcorresponding to the detected illuminance to the control unit 110according to the control unit 110.

The plurality of sensors included in the sensor unit 170 may beimplemented with separate Integrated Circuits (ICs or chips) or a singlechip (for example, a six-axis sensor including a geomagnetic sensor andan acceleration sensor or a nine-axis sensor including a geomagneticsensor, an accelerator sensor and a gyro sensor).

It may be easily understood by a person ordinarily skilled in the artthat the sensors of the sensor unit 170 may be added or omitteddepending on the performance of the head-mounted display device 100.

The storage unit 175 stores signals or data to be input/output inresponse to an operation of the mobile communication unit 120, thesub-communication unit 130, the multimedia unit 140, the camera unit150, the GPS unit 155, the input/output unit 160, the sensor unit 170,the display unit 190, or the light transmission unit 195 according tothe control unit 110. The storage unit 175 stores control programs forcontrolling the head-mounted display device 100 or the control unit 110,a Graphical User Interface (GUI) related to an application provided by amanufacture or downloaded from an external source, images for providingthe GUI, user information, a document, data bases, or associated data.

The term, “storage unit” in the present invention includes the storageunit 175, a ROM 112 or a RAM 114 within the control unit, or a memorycard which may be equipped in the head-mounted display device 100 (forexample, a micro Secure Digital (SD) card, and a memory stick). Thestorage unit 175 may include a non-volatile memory, a volatile memory, aHard Disc Drive (HDD), or a Solid State Drive (SSD).

The storage unit 175, according to an embodiment of the presentinvention, may store a command, a command list, notification, texts (forexample, Yes and No), an icon, an object, an application screen,contents displayed on the application screen, screen data, or varioussub-screens which are displayed on the display unit 190.

The storage unit 175 may store illuminance information (for example, anidentification ID for history management, an illuminance value,illuminance detecting time (for example, detecting time of theilluminance sensor 171 or receiving time for the communication unit)),or current position information (for example, an outdoor position by theGPS unit 155 or an indoor position by the mobile communication unit 120)which are received via the illuminance sensor 171 or the mobilecommunication unit 120. In addition, the storage unit 175 may includefirst illumination information or second illuminance information.

The storage unit 175 may store an application specification file (forexample, when the OS is Android, the application specification file is amanifest file application (AndroidManifest.xml)) including variousinformation items related to names and configurations of applications.In addition, the storage unit may store a program manager (for example,an activity manager or a package manager).

The storage unit 175 may store a light transmittance table. For example,the storage unit 175 may store a light transmittance table of anilluminance-application such as Table 1. The light transmittance tablemay be stored as a look-up table. The storage unit 175 may store anilluminance-light transmittance table (not illustrated). Further, thestorage unit 175 may store an application-light transmittance table (notillustrated).

Light transmittance information corresponding to a determined lighttransmittance may be stored in the storage unit 175. The lighttransmittance information may include an identification ID for historymanagement, a determined light transmittance, an illuminancecorresponding to the light transmittance, a determined application, acontent (or a content category) executed in the application, or thelike. In addition, the storage unit may store first light transmittanceinformation, second light transmittance information, or third lighttransmittance information.

The storage unit 175 may store a supply power table. For example, thestorage unit may store a light transmittance-supply power table such asTable 2. The supply power table may be stored as a look-up table. Thestorage unit 175 may store supply voltage information corresponding to adetermined supply voltage. The supply voltage information may include anidentification ID for history management, a determined supply voltage, alight transmittance corresponding to the supply voltage, illuminance, adetermined application, a content (or a content category) executed inthe application, or the like.

The storage unit 175 may store a user input (for example, the user'svoice, which is received through, for example, the microphone 162, theuser's motion, which may be detected through, for example, the sensor170, the user's touch, which is received through, for example, thebutton 161, or the user's touch gesture, which may be detected via thetouch pad 165, for example, a touch, a flick or a swipe).

The storage unit 175 may store a visual feedback (for example, a videosource) or an auditory feedback output from the speaker 163 to berecognized by the user, in response to a change of the lighttransmittance of the light transmission unit.

The power supply unit 180 supplies power to one or more batteriespositioned within the head-mounted display device 100. The one or morebatteries may be positioned in the second housing 30 and the fourthhousing 30 a. Further, the power supply unit 180 may supply power inputfrom an external power source via a wired cable connected to theconnector 164 to the head-mounted display device 100 according to thecontrol unit 110. In addition, the power supply unit 180 may supplypower to the head-mounted display device 100 via a wireless chargemethod (for example, a magnetic resonance method, an electromagneticwave method, or a magnetic induction method) according to the controlunit 110.

The display unit 190 may be a see-through display unit which may provideGraphical User Interfaces (GUIs) corresponding to various services (forexample, video call, data transmission, still image photography, videoimage photography, or an executed application screen) to the user. Thedisplay unit 190 may supply a GUI corresponding to a user input which isinput via the button 161, the microphone 162, the touch pad 165, or thesensor unit 170 to the user.

The display unit 190 may include a micro-display and an optical system.The display unit 190 may project an image displayed on the micro-display(for example, an LCD or an Organic LED (OLED)) to the user's eyes viathe optical system (for example, a free curved optical system),including a lens and a wave-guide.

The micro-display may include a display panel of, for example, a LiquidCrystal Display (LCD) type, an Organic Light Emitted Diode (OLED), or anActive Matrix Organic Light Emitted Diode (AMOLED).

A monocular-type display device includes a single display unit 190 thatdisplays contents. A binocular-type display device includes a pluralityof display units 190 and 190 a that may display a three-dimensionalimage.

The light transmission unit 195 adjusts the light transmittance of thetransmitted light in response to a supplied voltage or a suppliedcurrent. The light transmission unit 195 may be bonded to the front orrear surface of the optical lens 10 using an optically clear adhesive.In addition, the light transmission unit 195 may be bonded to the frontsurface of the optical system of the display unit 190 using theoptically clear adhesive.

The light transmittance of the light transmission unit 195 may beadjusted to be close to about 100% to transmit most of the light or tobe close to about 0% to prevent the transmission of most of the light inresponse to the supply voltage (or supply current) supplied to the lighttransmission unit 195.

The supply voltage may be adjusted such that the light transmittance ofthe light transmission unit 195 may have a value in a range from 0% to100% according to the control unit 110. According to an embodiment ofthe present invention, the light transmittance may have a value in arange from 5% to 95% according to the control unit 110. According to anembodiment of the present invention, the light transmittance may have avalue in a range from 10% to 80% according to the control unit 110. Someof the incident light may penetrate the light transmission unit 195 andthe remainder may be reflected by the light transmission unit 195depending on the light transmittance.

The light transmission unit 195 may include an electrochromic unit, asuspended particle unit, a liquid crystal unit, a photochromic unit, ora thermochromic unit.

The electrochromic unit changes the light transmittance using aphenomenon in which a color is reversibly changed depending on adirection of an electric field according to the supply voltage inputthereto. The electrochromic unit includes a material having an opticalcharacteristic which is reversibly changed by an electrochemicaloxidation-reduction reaction (which is included in, for example, anelectrochromic layer). The electrochromic unit produces a chemicalchange of the material, i.e. an oxidation or reduction reaction tochange a light transmittance (or a light reflectance) by using thesupply voltage (or current).

For example, the electrochromic material may include various organicmaterials, inorganic materials, or a combination of an organic materialand an inorganic material, such as titanium dioxide (TiO₂), Indium TinOxide (ITO), which is largely used as a transparent electrode material,an alloy of magnesium and calcium, or an alloy of magnesium andtitanium.

The suspended particle unit has a structure in which a conductive filmis arranged between two transparent plates (for example, ITO plates).The film contains fine dispersed and suspended particles which absorblight. When no supply voltage is input, the suspended particles absorblight and are seen as the color black. When a supply voltage is input,the suspended particles are aligned so as to transmit light. The supplyvoltage, which is adjusted manually or automatically, adjusts thetransmittance of transmitted light rapidly and accurately.

The liquid crystal in the liquid crystal unit has both of fluidity of aliquid and a regular molecule arrangement like solid crystals. Thearrangement of liquid crystal molecules is changed by the supplyvoltage, and when no supply voltage is input, the liquid crystalmolecules are returned to the original state thereof due to an elasticrestoring force. The liquid crystal unit changes the light transmittance(or light reflectance) using such an operating principle. The liquidcrystal unit may additionally change the light transmittance (or lightreflectance) via an alloy with a different metal. An electronic mirror(not illustrated) made of a combination of such compounds may befabricated in various types, such as a thin film type, a film type, anda glass type.

The photochromic unit changes light transmittance using a dye, of whicha color is transformed by ultraviolet rays or electrically generatedultraviolet rays (for example, D-shine photochromic dye).

The thermochromic unit changes light transmittance using a material, ofwhich a color changes according to a temperature.

At least one element may be added to the elements illustrated in thehead-mounted display device 100 of FIG. 1 or at least one of theelements illustrated in the head-mounted display device 100 may beomitted, depending on the performances of the head-mounted displaydevice 100. In addition, it may be easily understood by a personordinarily skilled in the art that the positions of the elements may bechanged depending on the performances or the structure of thehead-mounted display device 100.

FIG. 3 is a flowchart illustrating a method of changing a lighttransmittance of a head-mounted display device 100 according to anembodiment of the present invention.

FIGS. 4A to 4E are illustrations of a method of changing a lighttransmittance of a head-mounted display device 100 according to anembodiment of the present invention.

Referring to FIG. 3, an application is executed in step S301.

Referring to FIG. 4A, the user may see a real-world view 300 (forexample, an interior) via the head-mounted display device 100. Thereal-world view 300 is seen via the optical lens 10 and the lighttransmission unit 195. The display unit 190 is not operated since nopower is supplied according to the control unit 110. The lighttransmission unit 195 is also not operated since no power is suppliedaccording to the control unit 110.

Referring to FIG. 4B, a home screen 310 is displayed on the display unit190. The home screen 310 may display the user's position 311 (forexample, Seoul), the time 312 (for example, 12:45), or the weather 313(for example, an icon corresponding to it being sunny). The home screen310 may display the user's position 311, the time 312, and the weather313, selectively display a subset thereof, or none of them. The position311, the time 312, and the weather 313 may be displayed as a text, anicon, or an image.

Upon receiving a user input for operating the display unit 190, thedisplay device 100 is operated according to the control unit 110. Theuser input may be detected via the user's voice (for example, a voicereceived via the microphone 162), the user's motion (for example, amotion which may be detected via the sensor unit 170), the user's touch(for example, a touch received via the button 161), or the user's touchgesture (for example, a touch, flick, or swipe which may be detected viathe touch pad 165).

The home screen 310 is displayed to be distinct from the real-world view300 according to the control unit 110. For example, the control unit 110may display the edge of the home screen 310 to be distinct from thereal-world view 300 or display the brightness of the home screen 310 tobe dark. Meanwhile, the light transmission unit 195 is not operatedaccording to the control unit 110.

Referring to FIG. 4C, a screen of an executed application is displayedon the display unit 190.

The control unit 110 displays a screen 320 of an applicationcorresponding to a user input (for example, a screen of a movieapplication) on the display unit 190. Applications executable on thehead-mounted display device 100 may include, for example, a movieapplication, a music application, a photo application, a galleryapplication, a web browser application, an e-book (e-book reader)application, a game application, an augmented reality application, aSocial Network Service (SNS) application, a messenger application, andan object recognition application. In addition, the contents displayedon the application executed in the head-mounted display device 100 (or acontent category) may include, for example, a movie, an image, a text, aweb, music, or information. According to an embodiment of the presentinvention, the content may mean a content category.

One application may reproduce a dedicated content or various contents.For example, the movie application may reproduce a content, such as amovie or music. When a single application is capable of reproducingvarious contents, the control unit 110 determines the order of priority.For example, when a movie application is determined, the control unit110 may determine the movie as a preferentially executed content.

The control unit 110 displays a content (for example, a movie 321) inthe movie application displayed on the display unit 190.

In step S302 in FIG. 3, an illuminance is detected.

When an application is executed, the control unit 110 detects theilluminance around the head-mounted display device 100 using theilluminance sensor 171. The illuminance sensor 171 outputs anilluminance signal corresponding to the detected illuminance to thecontrol unit 110 (for example, an analog illuminance sensor may outputan analog signal and a digital illuminance sensor may output a digitalsignal). The control unit 110 calculates the illuminance using thereceived illuminance signal. The control unit 110 stores the calculatedilluminance in the storage unit 175 as detected illuminance information.The calculated illuminance may have a value in a range from 0 to 700lux.

An illuminance of artificial lighting (for example, studio lighting) maybe 1,000 lux, an outdoor illuminance in the daytime may be 10,000 to25,000 lux, and an illuminance of outdoor direct sunlight may be 32,000to 130,000 lux. An illuminance at sunrise or sunset may be 400 lux, andan luminance of a full moon adjacent to the equator may be 1 lux. Theilluminance detected in FIG. 4C or in step S302 in FIG. 3, for example,is 300 lux.

The calculated illuminance may be changed to correspond to the luminancerange detected by the illuminance sensor 171. In addition, thecalculated illuminance may be changed in correspondence with theaccuracy of the light transmittance which may be changed by the lighttransmission unit 195 (for example, in correspondence with the lighttransmittance to three decimal places).

When the application is executed, the control unit 110 detects theilluminance around the head-mounted display device 100 using the cameraunit 150. The control unit 110 calculates the illuminance usingluminance information of image data received via an image sensor of thecamera unit 150 (for example, a Charge-coupled Device (CCD) or aComplementary Metal Oxide Semiconductor (CMOS)) and a gain. The controlunit 110 stores the calculated illuminance in the storage unit 175 asphotographing illuminance information. The control unit 110 determinesthe light transmittance of the light transmission unit 195 using thestored photographing illuminance information.

When the application is executed, the control unit 110 receives theilluminance information around the head-mounted display device 100 froman external device via the mobile communication unit 120. The controlunit 110 stores the received illuminance in the storage unit 175 asreceived illuminance information.

The illuminance information includes at least one of the detectedilluminance information, the received illuminance information, and thephotographing illuminance information. For example, the illuminationinformation may include one of the detected illuminance information, thereceived illuminance information, and the photographing illuminanceinformation, or a combination of the detected illuminance information,the received illuminance information, and the photographing illuminanceinformation.

The control unit 110 determines the light transmittance of the lighttransmission unit 195 using the stored illuminance information (forexample, the detected illuminance information, the received illuminanceinformation, or the photographing illuminance information). When all thedetected illuminance information, the received illuminance information,and the photographing illuminance information are present in the storageunit, the control unit 110 may preferentially use the detectedilluminance information. The illuminance includes illuminanceinformation. For example, the detected illuminance may include thedetected illuminance information. The received illuminance may includethe received illuminance information. The photographing illuminance mayinclude the photographing illuminance information.

The stored illuminance information may include an identification ID forhistory management, an illuminance value, an illuminance detection time(for example, a detection time of the illuminance sensor 171, a signalreception time via the mobile communication unit 120, or a photographingtime via the camera unit 150), or present position information (forexample, an outdoor position by the GPS unit 155 or an indoor positionby the mobile communication unit 120).

Detected surrounding illuminances may include the detected illuminancevia the illuminance sensor 171, the received illuminance via the mobilecommunication unit 120, and the photographing illuminance via the cameraunit 150.

It may be easily understood by a person skilled in the art that when auser input is received not only in step S302 in FIG. 3 but also in stepS301 in FIG. 3, a periodic time interval (for example, 30 minutes) (thetime is variable), and a movement of the head-mounted display device 100may be detected by a sensor (for example, a gyro sensor 173, a motionsensor, or a geomagnetic sensor), or when the display unit 190 issupplied with power to operate, the control unit 110 detects thesurrounding illuminance.

In step S303 in FIG. 3, the executed application is determined.

Referring to FIG. 4C, the control unit 110 determines an applicationexecuted to correspond to the user input.

The control unit 110 determines the application executed using anapplication specification file including various information itemsrelated to a name and a configuration of the application. It may beeasily understood by a person ordinarily skilled in the art that theapplication specification file may be changed in terms of a file name ora file extension according to an Operating System (OS) installed in thehead-mounted display device 100.

In an embodiment of the present invention, it may be easily understoodby a person ordinarily skilled in the art, that the term “determine” afile stored in the storage unit (for example, a manifest file), a table(for example, a light transmittance table), or information (for example,illuminance information) includes meanings of “to figure out, “toidentify”, “to recognize”, “to read”, and “to decide”, and may beexpressed using various terms.

When the OS is Android, the application specification file includes amanifest file (AndroidManifest.xml). The manifest file defines a name,an icon, a version, authority, a service, an execution method of acorresponding application, or category information of the contentsdisplayed on the executed application (for example, a movie, an image, atext, a web, a music, or information). For example, in the case ofAndroid, the control unit 110 defines the content category information,such as “Intent.category information” or “action/category information”of an “intent-filter” of the manifest file and defines the content whichis being reproduced using a related Application Programming Interface(API). For example, a movie category may correspond to a videoapplication or a camera application. An image category may correspond toa gallery application. A music category may correspond to a musicapplication. A web category may correspond to a web browser application.A text category may correspond to an e-book application. In addition, aninformation (info) category may correspond to a message application oran SNS application.

In addition, the control unit 110 determines the executed applicationusing a program manager. The program manager manages a life cycle of theapplication (for example, execution and ending of the application). Theprogram manager includes an application manager.

In addition, the control unit 110 determines the executed applicationusing an extension of a content. For example, in a case of a content, ofwhich the extension is mpg, the control unit 110 determines the executedapplication as the video application. In a case of a content, of whichthe extension is Joint Photographic Expert Group (jpg), the control unit110 determines the executed application as the gallery application.

It may be easily understood by a person ordinarily skilled in the artthat the control unit 110 detects the surrounding illuminance even afterthe executed application is determined in step S303 in FIG. 3.

The light transmittance is determined in step S304 in FIG. 3.

The control unit 110 determines the light transmittance of the lighttransmission unit 195 using an illuminance and an application. Thecontrol unit 110 determines the light transmittance of the lighttransmission unit 195 using at least one of an illumination and anapplication stored in the storage unit 175. For example, the controlunit 110 may determine the light transmittance using one of theilluminance and the application or both the illuminance and theapplication.

In addition, the control unit 110 determines the light transmittance ofthe light transmission unit 195 using at least one of an illuminancestored in the storage unit 175 or a content executed in the application.For example, the control unit 110 may determine the light transmittanceusing one of the illuminance and the content executed in the applicationor both of the illuminance and the content executed in the application.

The following Table 1 stored in the storage unit 175 illustratesexamples of light transmittances determined using an illuminance and anapplication (or content).

TABLE 1 Content Illuminance Information (Lux) Movie Image Text Web Music(AR) 700 10% 10% 10% 10% 70% 70% 500 20% 20% 30% 30% 60% 60% 300 50% 50%60% 60% 50% 50% 100 70% 70% 80% 80% 70% 70% 50 80% 80% 80% 90% 90% 90% 0— — — — — —

Referring to Table 1, Content refers to contents executable in anapplication (or a content category), and Illuminance refers to adetected illuminance (or a received illuminance or a photographingilluminance). The control unit 110 may determine the corresponding lighttransmittance of the light transmission unit 195 with reference to Table1 stored in the storage unit 175. The light transmission unit 195 maychange the light transmittance in the range from 10% to 90% according tothe control unit 110. In addition, the light transmission unit 195 maychange the light transmittance in the range from 5% to 95%. In step S304in FIG. 3, when the detected illuminance is 300 lux and the determinedapplication is the movie application (or an executed content is amovie), the control unit 110 determines the light transmittance as 50%per Table 1.

It may be easily understood by a person ordinarily skilled in the artthat the light transmittance of Table 1 may be changed to correspond tothe performances and structure of the head-mounted display device 100.

The control unit 110 determines the light transmittance of the lighttransmission unit 195 using one of the illuminance, the determinedapplication, and the content executed in the application. In such acase, the control unit 110 may use Table 1 or another dedicated tablestored in the storage unit 175 separately from Table 1. The otherdedicated tables stored in the storage unit 175 may include, forexample, a light transmittance table corresponding to the illuminance ofthe light transmission unit 195, a light transmittance table of thelight transmission unit 195 corresponding to the application, or a lighttransmittance table of the light transmission unit 195 corresponding tothe content executed in the application.

When the executed application or the content displayed on theapplication is determined, the control unit 110 determines differentlight transmittances of light transmission unit 195 to correspond todetected illuminances, respectively. In addition, when illuminances aredetermined, the control unit 110 determines different transmittances ofthe light transmission unit 195 to correspond to executed applicationsor the contents reproduced in the applications, respectively. Even ifthe light transmittances of the light transmission unit 195 are thesame, at least one of the contents and the illuminances may bedifferent.

The control unit 110 stores first light transmittance informationcorresponding to the determined light transmittance in the storage unit175. The first light transmittance information may include, for example,an identification ID for history management, a determined lighttransmittance, a luminance corresponding to the light transmittance, adetermined application, or a content type executed in the application.

In step S305 in FIG. 3, a supply voltage is determined.

The control unit 110 determines the supply voltage to be supplied to thelight transmission unit 195 from the power supply unit 180 using Table 2stored in the storage unit 175 to correspond to the determined lighttransmittance.

The following Table 2 represents examples of supply voltagescorresponding to light transmittances determined according to anilluminance and an application.

TABLE 2 Light Transmittance (%) Voltage (V) 100 −1.85 90 −1.8 80 −1.5 70−1.0 60 −0.7 50 −0.55 40 −0.30 30 −0.05 20 0.3 10 0.45 0 0.6

Referring to Table 2, the supply voltage may be linearly changed from−1.85V to 0.6V depending on the light transmittance in percent (%),where the first column corresponds to the second column and the thirdcolumn corresponds to the fourth column. In step S305 in FIG. 3, thecontrol unit 110 may determine a supply voltage corresponding to thelight transmittance of 50% as −0.55V.

The control unit 110 determines the supply voltage using interpolationfor a light transmittance which is not indicated in Table 2. The supplyvoltages of Table 2 are those in a state where a residual capacity ofthe power supply unit 180 or a battery of the head-mounted displaydevice 100 is normal. When the residual capacity of the battery of thehead-mounted display device 100 is insufficient (for example, in alow-battery state), the control unit 110 determines a supply voltagewhich is different from that in Table 2 to correspond to the determinedlight transmittance.

The control unit 110 stores supply voltage information corresponding tothe determined supply voltage in the storage unit 175. The supplyvoltage information may include, for example, an identification ID forhistory management, a determined supply voltage, a light transmittancecorresponding to the supply voltage, an illuminance, a determinedapplication, or a content executed in the application.

It may be easily understood by a person ordinarily skilled in the artthat the supply voltages in Table 2 may be changed to correspond to theperformances and structure of the head-mounted display device 100. Inaddition, it may be easily understood by a person ordinarily skilled inthe art that the supply voltages in Table 2 may be converted to supplycurrents.

In step S306 in FIG. 3, the light transmittance of the lighttransmission unit is changed.

Referring to FIG. 4D, the control unit 110 changes the lighttransmittance of the light transmission unit 195. The control unit 110changes the supply voltage to correspond to the determined lighttransmittance supplied to the light transmission unit 195. Thereal-world view 300 of FIG. 4C is changed to another rear-world view 300a in FIG. 4D to correspond to the changed light transmittance (forexample, 50%) of the light transmission unit 195. The user may watchboth of the another real-world view 300 a and the movie 321 displayed onthe display unit 190. The user is provided with improved visibility ofthe movie 321 displayed on the display unit 190 because of the anotherreal-world view 300 a. Further, the user may become more absorbed in thedisplayed movie 321 because of the another real-world view 300 a.

The control unit 110 provides various feedback in response to a changeof the light transmittance of the light transmission unit 195. Thefeedback may be provided as one of, for example, a visual feedback or anauditory feedback. In addition, the control unit 110 may provide boththe visual feedback and the auditory feedback in response to a change ofthe light transmittance. In addition, if the head-mounted display device100 includes a vibration motor, the control unit 110 provides a tactilefeedback to the user using the vibration motor.

With the visual feedback, a visual effect in response to a change of thelight transmittance of the light transmission unit 195 (for example, aneffect of changing the light transmittance to be visually different fromthe current light transmittance according to the determined lighttransmittance) is provided by the light transmission unit 195. Inaddition to the visual feedback, another visual effect (for example, ananimation effect such as a separate image or fading applied to thenon-illustrated separate image) may be provided by the display unit 190.Further, in addition to the visual feedback, the above-described visualeffects in response to a change of the light transmittance of the lighttransmission unit 195 may be provided by both the light transmissionunit 195 and the display unit 190.

The auditory feedback may output a sound in response to a change of thelight transmittance of the light transmission unit 195 through thespeaker 163.

At least one feedback may be maintained from the start of a change ofthe light transmittance of the light transmission unit 195 to thecompletion of a change of the light transmittance. A feedbackcorresponding to a change of the light transmittance of the lighttransmission unit 195 (for example, at least one of the visual feedbackand the auditory feedback) may be selected and/or changed through theconfiguration of the OS. The control unit 110 sets and/or changes alength of time in which at least one feedback corresponding to a changeof the light transmittance of the light transmission unit 195 isprovided to the user (for example, 500 msec) by a user input.

In step S307 in FIG. 3, the changed light transmittance is set.

Referring to FIG. 4E, the control unit 110 displays a popup 330 and/or apointer 331 for setting a changed light transmittance on the displayunit 190. The popup 330 and/or the pointer 331 is displayed on thereproduced movie 321 to be distinctive from the movie 321. The pointer331 may be positioned at “Yes” 332 as a default value. “Yes” 332 or “No”331 may be input by a user input. When “Yes” 332 is selected by the userinput, the control unit 110 sets the changed light transmittance.

In step S308 in FIG. 3, the changed light transmittance is stored.

The control unit 110 stores a second light transmittance informationcorresponding to the set light transmittance in the storage unit 175.The second light transmittance information may include an indication IDfor history management, the set light transmittance, a luminancecorresponding to the light transmittance, a determined application, or acontent executed in the application. When the light transmittance set instep S307 in FIG. 3 is equal to the light transmittance determined instep S304 in FIG. 3, the first light transmittance information is equalto the second light transmittance information.

When a changed light transmittance is stored in step S308 in FIG. 3, themethod of changing the light transmittance of the head-mounted displaydevice 100 ends.

According to another embodiment of the present invention, the method ofchanging the light transmittance of the head-mounted display device 100may be ended when the light transmittance changed in step S308 in FIG. 3is directly stored, skipping step S307 in FIG. 3 without setting thelight transmittance changed by the user input in step S307 in FIG. 3.

Returning to step S307 in FIG. 3, when a changed light transmittance isnot set, the process proceeds to step S309 in FIG. 3.

In step S309 in FIG. 3, the light transmittance is changed manually.

Referring to FIG. 4E, when “No” 333 is selected by the user input, thecontrol unit 110 allows the light transmittance determined in step S304in FIG. 3 to be manually changed by user input. The user input which maymanually change the light transmittance may include the user's voice(for example, a voice received through the microphone 162), the user'smotion (for example, a motion detected through the sensor unit 170), theuser's touch (for example, a touch received through the button 161), orthe user's touch gesture (for example, a touch, flick or swipe detectedthrough the touch pad 165).

The control unit 110 changes the light transmittance of the lighttransmission unit 195 (for example, an automatically determined lighttransmittance) separately from the movie displayed on the display unit190, in response to a user input. The present light transmittance (forexample, 50%) may be increased (for example, to 51% or more) ordecreased (for example, to 49% or less) by the control unit 110 based onthe user input. When the light transmittance is determined based on auser input, the control unit 110 determines the supply voltagecorresponding to the manually determined light transmittance using Table2. The power supply unit 180 supplies the supply voltage correspondingto the manually determined light transmittance to the light transmissionunit 195 according to the control unit 110.

When the light transmittance is manually changed in step S309 in FIG. 3,the process proceeds to step S308 in FIG. 3.

In step S308 in FIG. 3, the changed light transmittance is stored.

The control unit 110 may store a third light transmittance informationcorresponding to the manually set light transmittance in the storageunit 175. The third light transmittance information may include anidentification ID for history management, the set light transmittance, aluminance corresponding to the light transmittance, a determinedapplication, or a content executed in the application.

When the manually changed light transmittance is stored in step S308 inFIG. 3, the method of changing the light transmittance of thehead-mounted display device 100 ends.

FIGS. 5A and 5B are illustrations of a method of changing a lighttransmittance of the head-mounted display device, according to anembodiment of the present invention.

FIGS. 5A and 5B illustrates a case in which detected illuminances aredifferent from each other and determined applications are equal to eachother, unlike FIGS. 4A to 4E.

Referring to 5A, the user may watch a real-world view 400 (for example,an outdoor sports stadium) through the head-mounted display device 100.When the display unit 190 is operated, the control unit 110 detects anilluminance. Since it is outdoor and daylight, the detected illuminancemay be 700 lux.

The control unit 110 determines an executed application 420 as a movieapplication (or a content executed as movie 421). The control unit 110may determine the light transmittance corresponding to the detectedilluminance and the determined application (or the movie as the contentexecuted therein) to be 10% using Table 1. In addition, the control unitdetermines the supply voltage corresponding to the determined lighttransmittance of 10% to be 0.45 volts using Table 2.

Referring to FIG. 5B, the control unit 110 changes the lighttransmittance of the light transmission unit 195. The power supply unit180 supplies the determined supply voltage of 0.45 volts to the lighttransmission unit 195 according to the control unit 110. The real-worldview 400 of FIG. 5A is changed to another real-world view 400 a in FIG.5B to correspond to the changed light transmittance (for example, 10%)of the light transmission unit 195. The user may watch both the anotherreal-world view 400 a and the movie 421 displayed on the display unit190. The user is provided with improved visibility of the movie 421displayed on the display unit 190 because of the another real-world view400 a. In addition, the user may become more adsorbed in the displayedmovie due to the another real-world view 400 a.

FIGS. 6A and 6B are illustrations of a method of changing the lighttransmittance of the head-mounted display device 100, according to anembodiment of the present invention.

FIGS. 6A and 6B illustrate a case in which detected illuminances aredifferent from each other and determined applications are equal to eachother, unlike FIGS. 4A to 4E.

Referring to FIG. 6A, the user may watch a real-world view 500 (forexample, an indoor dark hallway) through the head-mounted display device100. When the display unit 190 is operated, the control unit 110 detectsan illuminance. Since it is indoor and dark, the detected illuminancemay be 100 lux.

The control unit 110 determines an executed application 520 as a movieapplication (or a content executed therein as a movie 521). The controlunit 110 may determine the light transmittance corresponding to thedetected illuminance and the determined application (or the movie as thecontent executed therein) as 70% using Table 1. In addition, the controlunit 110 determines the supply voltage corresponding to the determinedlight transmittance of 70% as −1.0 volts using Table 2.

Referring to FIG. 6B, the control unit 110 changes the lighttransmittance of the light transmission unit 195. The power supply unit180 supplies the determined supply voltage of −1.0 volts to the lighttransmission unit 195 according to the control unit 110. The real-worldview 500 is changed to another real-world view 500 a to correspond tothe changed light transmittance (for example, 70%) of the lighttransmission unit 195. The user may watch both the another real-worldview 500 a and the movie 521 displayed on the display unit 190. The useris provided with improved visibility of the movie 521 displayed on thedisplay unit 190 because of the another real-world view 500 a. Further,the user may become more absorbed in the displayed movie because of theanother real-world view 500 a.

FIGS. 7A and 7B are illustrations of a method of changing the lighttransmittance of the head-mounted display device 100, according to anembodiment of the present invention.

FIGS. 7A and 7B illustrate a case in which detected illuminances areequal to each other and determined applications are different from eachother, unlike FIGS. 4A to 4E.

Referring to FIG. 7A, the user may watch a real-world view 600 (forexample, indoor relics) through the head-mounted display device 100.When the display unit 190 is operated, the control unit 110 detects anilluminance. Since it is indoor and bright, the detected illuminance maybe 300 lux.

The control unit 110 may determine an executed application 620 as anobject recognition application (or a content executed therein asinformation 621). The control unit 110 may determine the lighttransmittance corresponding to the detected illuminance and thedetermined application (or the information as the content executedtherein) as 50% using Table 1. In addition, the control unit 110determines the supply voltage corresponding to the determined lighttransmittance of 50% as −0.55 volts using Table 2.

Referring to FIG. 7B, the control unit 110 changes the lighttransmittance of the light transmission unit 195. The power supply unit180 supplies the determined supply voltage of −0.55 volts to the lighttransmission unit 195 according to the control unit 110. The real-worldview 600 is changed to another real-world view 600 a to correspond tothe changed light transmittance (for example, 50%) of the lighttransmission unit 195. The user may watch both the another real-worldview 600 a and the information displayed on the display unit 190. Theuser is provided with improved visibility of the information displayedon the display unit 190 because of the another real-world view 600 a.

FIGS. 8A and 8B are illustrations of a method of changing the lighttransmittance of the head-mounted display device 100, according to anembodiment of the present invention.

FIGS. 8A and 8B illustrate a case in which detected illuminances aredifferent from each other and determined applications are also differentfrom each other, unlike FIGS. 4A to 4E.

Referring to FIG. 8A, the user may watch a real-world view 700 (forexample, indoor relics) through the head-mounted display device 100.When the display unit 190 is operated, the control unit 110 detects anilluminance. Since it is indoor and darker than FIG. 7A, and thedistance between the user and the relics are longer than that in FIG.7A, the detected illuminance may be 100 lux.

The control unit 110 may determine an executed application 720 as anobject recognition application (or a content executed therein asinformation 721). The control unit 110 may determine the lighttransmittance corresponding to the detected illuminance and thedetermined application (or the information as the content executedtherein) as 70% using Table 1. In addition, the control unit 110determines the supply voltage corresponding to the determined lighttransmittance of 70% as −1.0 volts using Table 2.

Referring to FIG. 8B, the control unit 110 changes the lighttransmittance of the light transmission unit 195. The power supply unit180 supplies the determined supply voltage of −1.0 volts to the lighttransmission unit 195 according to the control unit 110. The real-worldview 700 is changed to another real-world view 700 a to correspond tothe changed light transmittance (for example, 70%) of the lighttransmission unit 195. The user may watch both the another real-worldview 700 a and the information displayed on the display unit 190. Theuser is provided with improved visibility of the information displayedon the display unit 190 because of the another real-world view 700 a.

The methods according to embodiments of the present invention may beimplemented in a form of program commands executed through variouscomputer means to be recorded in a non-transitory computer-readablemedium. The non-transitory computer-readable medium may include aprogram command, a data file, and a data structure individually or acombination thereof. Software may be stored, for example, in a volatileor non-volatile storage device such as a ROM, a memory such as a RAM, amemory chip, a memory device, or a memory IC, or a storage medium thatis optically or magnetically recordable and simultaneously machine (forexample, a computer) readable, such as a Compact Disc (CD), a DigitalVideo Disc (DVD), a magnetic disk, or a magnetic tape, regardless of itsability to be erased or re-recorded. It can be seen that a memory whichmay be included in the head-mounted display device corresponds to anexample of the storage medium suitable for storing a program or programsincluding instructions by which the embodiments of the present inventionare realized. The program command recorded in the medium is speciallydesigned and configured for the present invention, but may be used afterbeing known to those skilled in computer software fields.

Although the present invention has been described by the embodiments andthe drawings as described above, the present invention is not limited tothe aforementioned embodiments and various modifications and alterationscan be made from the descriptions by those skilled in the art to whichthe present invention pertains.

Accordingly, the scope of the present invention should not be determinedby the above-described embodiments, but should be determined by not onlythe following claims but also their equivalents.

What is claimed is:
 1. A method of changing a light transmittance of ahead-mounted display device including a display and an optical lens, themethod comprising: obtaining, by a sensor, a first illuminance aroundthe head-mounted display device; determining a first light transmittancebased on the first illuminance and a type of a content to display on thedisplay; changing, by a processor, a light transmittance of the opticallens to the first light transmittance; and wherein when the firstilluminance is greater than a second illuminance, the first lighttransmittance corresponding to the first illuminance is less than asecond light transmittance corresponding to the second illuminance. 2.The method of claim 1, further comprising: determining a supply voltagecorresponding to the first light transmittance, wherein the supplyvoltage is supplied to a light transmission unit included in thehead-mounted display device.
 3. The method of claim 1, wherein the firstilluminance is at least one of a third illuminance detected through thesensor and a fourth illuminance received by an external device.
 4. Themethod of claim 1, wherein determining the first light transmittanceincludes determining the first light transmittance further based oninformation of an application.
 5. The method of claim 1, whereindetermining the first light transmittance includes determining the firstlight transmittance further based on at least one of a program managerthat manages a life cycle of the application, and an applicationspecification file that includes information of the application.
 6. Themethod of claim 5, wherein the program manager includes an activitymanager or a package manager.
 7. The method of claim 1, wherein thefirst light transmittance is changeable by a user input.
 8. The methodof claim 1, further comprising changing a visibility of the contentincluded in the application to a first visibility corresponding to thefirst light transmittance.
 9. The method of claim 1, wherein the firstlight transmittance is changeable in a range from 5% to 95%.
 10. Themethod of claim 2, wherein the light transmission unit includes one ofan electrochromic unit, a suspended particle unit, a liquid crystalunit, a photochromic unit, and a thermochromic unit.
 11. The method ofclaim 1, further comprising providing at least one of a visual feedbackand an auditory feedback to indicate the changing of the lighttransmittance of the optical lens.
 12. A head-mounted display device,comprising: a sensor; a display; a light transmission unit configured toadjust a light transmittance of an optical lens included in thehead-mounted display device; and a controller configured to: obtain,using the sensor, a first illuminance around the head-mounted displaydevice, determine a first transmittance based on the first illuminanceand a type of the content to display on the display, and change thelight transmittance of the optical lens to the first lighttransmittance, wherein when the first illuminance is greater than asecond illuminance, the first light transmittance corresponding to thefirst illuminance is less than a second light transmittancecorresponding to the second illuminance.
 13. The head-mounted displaydevice of claim 12, wherein the first illuminance is at least one of athird illuminance detected through the sensor and a fourth illuminancereceived by an external device.
 14. The head-mounted display device ofclaim 12, wherein the controller is further configured to supply asupply voltage corresponding to the light transmittance from a powersupply to the light transmission unit.
 15. The head-mounted displaydevice of claim 12, wherein the light transmission unit includes one ofan electrochromic unit, a suspended particle unit, a liquid crystalunit, a photochromic unit, and a thermochromic unit.
 16. Thehead-mounted display device of claim 12, wherein the light transmissionunit includes an electrochromic unit, wherein the electrochromic unitincludes: a first Indium Tin Oxide (ITO) layer; an electrochromic layeron the first ITO layer, wherein a light transmittance of theelectrochromic layer is changeable via a supply voltage; an electrolytelayer on the electrochromic layer; a second ITO layer on the electrolytelayer; and a plurality of electrodes connected with the first ITO layerand the second ITO layer, respectively, wherein the supply voltage isinput to the plurality of electrodes.
 17. The head-mounted displaydevice of claim 12, wherein the light transmission unit is bonded to oneof a front surface and a rear surface of the optical lens.
 18. Thehead-mounted display device of claim 12, wherein a screen of the contentdisplayed on the display is smaller than the optical lens.